CVE-2026-23963 describes a resource exhaustion vulnerability in Mastodon versions prior to 4.5.5, 4.4.12, and 4.3.18. The flaw allows any local user to set arbitrarily long names for lists, filters, or filter keywords, leading to disproportionate storage and computing resource usage. Rated Medium severity with a CVSS score of 6.5, this vulnerability has a low attack complexity and can result in high availability impact, potentially rendering a user's own web interface unusable. There is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or KEV listing, though it has garnered some community discussion with 10 mentions.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
< 4.3.18CPE matchmatch criteria | cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:* | ||
>= 4.4.0, < 4.4.12CPE matchmatch criteria | cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:* | ||
>= 4.5.0, < 4.5.5CPE matchmatch criteria | cpe:2.3:a:joinmastodon:mastodon:*:*:*:*:*:*:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.
No media coverage found for this CVE.
The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.